Mercury Exposure in Diabetic Rats

Abstract

Diabetes is a significant health problem and comorbidity throughout the world that can lead to renal injury and insufficiency. Exposure to environmental toxicants such as mercury (Hg) may also lead to renal injury and insufficiency. Indeed, exposure to Hg has been shown to exacerbate chronic kidney disease (CKD). However, the impact of Hg exposure on renal function in diabetic patients is unclear. The goal of the present study is to test the hypothesis that exposing diabetic animals to Hg will enhance renal injury. To test this hypothesis, we used diabetic and control Wistar rats. Diabetic rats (n = 10) were fed a high-fat diet for 10 days followed by an injection with streptozotocin (65 mg/kg). Control rats (n = 10) were fed a normal diet for 10 days followed by an injection of buffer. Rats with blood glucose levels above 150 mg/dL were considered diabetic. Five rats from each group were administered Hg (5 mg/kg) intravenously and the remaining five rats were administered saline. Rats were sacrificed 24 h after injection, and we measured biomarkers of renal function. Diabetic rats had decreased renal function, evidenced by increased serum creatinine levels and KIM-1 expression. Additionally, the expression of Klotho, SIRT1, and ATG13 was decreased, suggesting impairment in some cellular homeostatic processes. Histological analyses revealed pathological changes in diabetic rat kidneys. The current study provides data related to the mechanisms of renal injury in diabetic patients and shows that, under the current exposure conditions, exposure to Hg does not enhance renal injury in diabetic patients.